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/*
* Copyright 2018-present Open Networking Foundation
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* http://www.apache.org/licenses/LICENSE-2.0
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package adaptercore
import (
"reflect"
"runtime"
"github.com/opencord/voltha-go/common/log"
)
// DeviceState OLT Device state
type DeviceState int
const (
// deviceStateNull OLT is not instantiated
deviceStateNull DeviceState = iota
// deviceStateInit OLT is instantiated
deviceStateInit
// deviceStateConnected Grpc session established with OLT
deviceStateConnected
// deviceStateUp Admin state of OLT is UP
deviceStateUp
// deviceStateDown Admin state of OLT is down
deviceStateDown
)
// Trigger for changing the state
type Trigger int
const (
// DeviceInit Go to Device init state
DeviceInit Trigger = iota
// GrpcConnected Go to connected state
GrpcConnected
// DeviceUpInd Go to Device up state
DeviceUpInd
// DeviceDownInd Go to Device down state
DeviceDownInd
// GrpcDisconnected Go to Device init state
GrpcDisconnected
)
// TransitionHandler function type for handling transition
type TransitionHandler func() error
// Transition to store state machine
type Transition struct {
previousState []DeviceState
currentState DeviceState
before []TransitionHandler
after []TransitionHandler
}
// TransitionMap to store all the states and current device state
type TransitionMap struct {
transitions map[Trigger]Transition
currentDeviceState DeviceState
}
// OpenoltDevice state machine:
//
// null ----> init ------> connected -----> up -----> down
// ^ ^ | ^ | |
// | | | | | |
// | +-------------+ +---------+ |
// | |
// +-----------------------------------------+
// NewTransitionMap create a new state machine with all the transitions
func NewTransitionMap(dh *DeviceHandler) *TransitionMap {
var transitionMap TransitionMap
transitionMap.currentDeviceState = deviceStateNull
transitionMap.transitions = make(map[Trigger]Transition)
// In doInit establish the grpc session
transitionMap.transitions[DeviceInit] =
Transition{
previousState: []DeviceState{deviceStateNull},
currentState: deviceStateInit,
before: []TransitionHandler{dh.doStateInit},
after: []TransitionHandler{dh.postInit}}
// If gRpc session fails, re-establish the grpc session
transitionMap.transitions[GrpcDisconnected] =
Transition{
previousState: []DeviceState{deviceStateConnected, deviceStateDown},
currentState: deviceStateInit,
before: []TransitionHandler{dh.doStateInit},
after: []TransitionHandler{dh.postInit}}
// in doConnected, create logical device and read the indications
transitionMap.transitions[GrpcConnected] =
Transition{
previousState: []DeviceState{deviceStateInit},
currentState: deviceStateConnected,
before: []TransitionHandler{dh.doStateConnected}}
// Once the olt UP is indication received, then do state up
transitionMap.transitions[DeviceUpInd] =
Transition{
previousState: []DeviceState{deviceStateConnected, deviceStateDown},
currentState: deviceStateUp,
before: []TransitionHandler{dh.doStateUp}}
// If olt DOWN indication comes then do sate down
transitionMap.transitions[DeviceDownInd] =
Transition{
previousState: []DeviceState{deviceStateUp},
currentState: deviceStateDown,
before: []TransitionHandler{dh.doStateDown}}
return &transitionMap
}
// funcName gets the handler function name
func funcName(f interface{}) string {
p := reflect.ValueOf(f).Pointer()
rf := runtime.FuncForPC(p)
return rf.Name()
}
// isValidTransition checks for the new state transition is valid from current state
func (tMap *TransitionMap) isValidTransition(trigger Trigger) bool {
// Validate the state transition
for _, state := range tMap.transitions[trigger].previousState {
if tMap.currentDeviceState == state {
return true
}
}
return false
}
// Handle moves the state machine to next state based on the trigger and invokes the before and
// after handlers
func (tMap *TransitionMap) Handle(trigger Trigger) {
// Check whether the transtion is valid from current state
if !tMap.isValidTransition(trigger) {
log.Errorw("Invalid transition triggered ", log.Fields{"CurrentState": tMap.currentDeviceState, "Trigger": trigger})
return
}
// Invoke the before handlers
beforeHandlers := tMap.transitions[trigger].before
if beforeHandlers != nil {
for _, handler := range beforeHandlers {
log.Debugw("running-before-handler", log.Fields{"handler": funcName(handler)})
if err := handler(); err != nil {
// TODO handle error
return
}
}
} else {
log.Debugw("No handlers for before", log.Fields{"trigger": trigger})
}
// Update the state
tMap.currentDeviceState = tMap.transitions[trigger].currentState
log.Debugw("Updated device state ", log.Fields{"CurrentDeviceState": tMap.currentDeviceState})
// Invoke the after handlers
afterHandlers := tMap.transitions[trigger].after
if afterHandlers != nil {
for _, handler := range afterHandlers {
log.Debugw("running-after-handler", log.Fields{"handler": funcName(handler)})
if err := handler(); err != nil {
// TODO handle error
return
}
}
} else {
log.Debugw("No handlers for after", log.Fields{"trigger": trigger})
}
}